On straight bar knitting machines bearded needles are mounted on a common needle bar which causes all the needles to move simultaneously during a knitting operation. Jacks of jack bar assemblies are used to advance sinkers in a predetermined manner successively between adjacent needles so as to form kinks of yarn. The jacks are actuated by a slurcock.
In known straight bar knitting machines, a slurcock engages jacks midway at their rear. The slurcock cams the jacks forward and the jacks in turn slide sinkers forward on a sinker bar. The slurcocks have an increasingly steep profile so that the sinkers are advanced rapidly at the final part of their advance. Such sinker actuating systems, using slurcocks and jacks are noisy, subject to wear and may malfunction at high draw speeds (that is the speed of slurcock traverse along the rear of the jacks).